NACE Definition of Sour Service

[jcmme]

Good morning:

I am looking for a definition of sour service for hydrocarbon piping systems

Thanks,

 

[gr2vessels]

Refer to Chapter 6, clause 6.1 and 6.2 of NACE MR0175 / ISO 15156. Also, try the Search button above, select the search posts in the advance search pull down menu.
Cheers,
gr2vessels

 

[strider6]

sour service is a service which contains H2S above a certain threshold (partial pressure above 15 psi or 3 mBar) and a free water phase.


S.



Corrosion Prevention & Corrosion Control

 

[SJones]

thread338-227948


Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[strider6]

sorry.. 0.05 psi of partial pressure not 15 psi...

S.

Corrosion Prevention & Corrosion Control

 

[arunmrao]

The definition of sour service corrosion in common terms is a wet hydrogen sulphide containing environment.

According to ISO 15156
‘Exposure to oilfield environments that contain H2S and can cause cracking of materials by the mechanisms addressed by ISO 15156 Part 1’

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

 

[jcmme]

The calculation of the H2S partial pressure on MR0175-2002 for crude oil systems involves the use of the bubble point pressure.
Does anyone know if we could use any other pressure such as the system design pressure or the normal operating pressure?

Thx

 

[SJones]

If you are in a gas free, liquid full system without any process data for an equilibrium gas phase - how else will you determine a gas phase partial pressure of H2S? Refer to Annex C of ISO 15156-2.

Since SSC is a non age related degradation mechanism and is dependent upon pH2S, it is prudent to calculate pH2S from system DESIGN pressure in gas containing systems. The actual choice would be dependent upon the likelihood of achieving design pressure within the pressure system. See the thread in process engineering thread798-227400 which has everyone in a fluster.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[jcmme]

Thanks all for your help.

Regards,